Pilot Valve Attachment Structure of Construction Machine

ABSTRACT

Provided is a pilot valve attachment structure of a construction machine which can reduce an oppressive sensation that an operator sitting on an operator&#39;s seat may feel. The present invention is provided in a compact excavator having a travel operation device  11  including a pilot valve  18,  and configured such that the pilot valve  18  is attached to a floor plate  15,  wherein a recessed part  20  having a hole  20   b,  into which a casing  18   a  forming an outer frame of the pilot valve  18  can be inserted, on a bottom part  20   a  thereof is provided on the floor plate  15,  the casing  18   a  of the pilot valve  18  is attached to the bottom part  20   a  of the recessed part  20  in a state where the casing  18   a  of the pilot valve  18  is inserted into the hole  20   b  of the recessed part  20,  and a mat shaped seal member  21  for sealing a space that is formed around the casing  18   a  of the pilot valve  18  when the casing  18   a  is inserted into the hole  20   b  of the recessed part  20.

TECHNICAL FIELD

The present invention relates to a pilot valve attachment structure of aconstruction machine, which is provided in a construction machine suchas a compact excavator and is configured such that a pilot valveincluded in a travel operation device arranged in front of an operator'sseat is attached to a floor plate.

BACKGROUND ART

Regarding the techniques above, JP 2011-64064 A (Patent document 1)describes the prior arts. The techniques disclosed in Patent document 1relates to a structure in which a pilot valve included in a traveloperation device provided in an excavator having an travel base, aupperstructure, and a working device is attached to a flat-shaped floorof an operator's seat, that is, a floor plate.

PRIOR ART DOCUMENT Patent Document

Patent Document 1: Japanese Patent Application Laid-Open No. 2011-64064A

SUMMARY Problems to be Solved by the Invention

In the conventional techniques according to Patent document 1 describedabove, because the pilot valve is attached to the flat-shaped floorplate, a height dimension of a part of the pilot valve which projectsupwardly from the floor plate becomes large. As a result of this, anoperation space for the travel operation device arranged in front of theoperator's seat tends to become small, and accordingly, an operatorsitting on the operator's seat is likely to feel an oppressivesensation. They are especially disadvantageous when a constructionmachine provided with the pilot valve according to the conventionaltechniques is a small machine such as a small excavator where the sizeof an operation space of a travel operation device tends to be limitedin its manufacture.

The present invention was made in view of such problems stemming fromthe conventional techniques described above, and an object of thepresent invention is to provide a pilot valve attachment structure of aconstruction machine which can reduce an oppressive sensation that anoperator sitting on an operator's seat is likely to feel.

Means for Solving the problem

In order to achieve the object described above, the present inventionprovides a pilot valve attachment structure of a construction machinethat includes a travel base, a upperstructure arranged on the travelbase, a working device attached to the upperstructure, an operator'sseat arranged on a floor plate that is formed on the upperstructure, anda travel operation device arranged in front of the operator's seat andhaving a pilot valve, the pilot valve included in the travel operationdevice being attached to the floor plate, wherein a recessed part havinga hole, into which a casing forming an outer frame of the pilot valvecan be inserted, on a bottom part thereof is provided on the floorplate, the casing of the pilot valve is attached to the bottom part ofthe recessed part in a state where the casing of the pilot valve isinserted into the hole of the recessed part, and a mat shaped sealmember for sealing a space that is formed around the casing of the pilotvalve when the casing is inserted into the hole of the recessed part.

The present invention is configured such that the casing of the pilotvalve is attached on the bottom part of the recessed part of the floorplate, and accordingly, the casing of the pilot valve can be attached tothe floor plate such that the top surface of the pilot valve projectingfrom the top surface of the floor plate is low. Because the recessedpart is formed in the floor plate, there is concern that contaminants,such as mud or muddy water, may enter the inside of the pilot valvethrough the recessed part, however, the mat shaped seal member thatseals a space formed around the casing of the pilot valve can preventthe contaminants such as mud or muddy water from entering the inside ofthe pilot valve.

Furthermore, according to the present invention, the mat shaped sealmember is made of a rubber member. With this configuration, the matshaped seal member can be bended due to elasticity and is easilyattached to or removed from the recessed part of the floor plate.

Furthermore, according to the present invention, the mat shaped sealmember consists of a first divided member and a second divided memberthat are dividedly formed so as to interpose the casing of the pilotvalve therebetween. With this configuration, because the mat shaped sealmember is dividedly formed into the first divided member and the seconddivided member so as to be separated with each other, an operation fordisposing the mat shaped seal member around the casing of the pilotvalve can be easily performed.

Furthermore, according to the present invention, the mat shaped sealmember includes a projection part on a lower side thereof, and a holepart into which the projection part is inserted is formed on the bottompart of the recessed part. With this configuration, because theprojection part of the mat shaped seal member is inserted into the holepart of the floor plate, it is possible to easily position the matshaped seal member within the recessed part and to stably hold the matshaped seal member which is attached to the recessed part of the floorplate, without causing any positional deviation with respect to therecessed part.

Furthermore, according to the present invention, the mat shaped sealmember is attached to the recessed part so that a top surface of the matshaped seal member forms approximately the same plane as a top surfaceof the floor plate and the top surface of the mat shaped seal memberbecomes in the height equal to or higher than that of the floor plate.With this configuration, because the mat shaped seal member is attachedto the recessed part such that the top surface of the mat shaped sealmember forms approximately the same plane as that of the floor plate andthe top surface of the mat shaped seal member becomes in the heightequal to or higher than that of the floor plate, contaminants such asmud or muddy water hardly enter the recessed part, and thus it ispossible to certainly prevent the contaminants from entering the insideof the pilot valve.

Effect of the Invention

The present invention is configured such that a pilot vale is attachedto a recessed part formed in a floor plate, and accordingly, a part ofthe pilot valve projecting from the floor plate can be made lower thanthat of a conventional structure. With this configuration, an oppressivesensation that an operator sitting on the operator's seat is likely tofeel in a limited narrow operation space can be reduced, and it ispossible to secure a comfortable operability more than before.Furthermore, because a mat shaped seal member seals a space formedaround the pilot valve, it is possible to prevent contaminants such asmud or muddy water from entering the inside of the pilot valve, and thusit is possible to realize to maintain good performance of the pilotvalve as well as to secure excellent durability thereof.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a side view of a compact excavator illustrated as an exampleof a construction machine provided with an embodiment of a pilot valveattachment structure according to the present invention.

FIG. 2 is a perspective view of an arrangement part of an operator'sseat provided in the compact excavator illustrated in FIG. 1.

FIG. 3 is an enlarged perspective view of a main part where an operationpedal, etc is removed from a state illustrated in FIG. 2.

FIG. 4 is a perspective view of a part of FIG. 3, which is illustratedfrom another angle.

FIG. 5 illustrates relationship of stepping-on action of an operationpedal and the height of a casing of a pilot valve.

FIG. 6 illustrates a mat shaped seal member provided in the presentembodiment, in particular, FIG. 6( a) is a perspective view illustratedfrom a front side, and FIG. 6( b) is a perspective view illustrated froma back side.

FIG. 7 illustrates relationship of attachment between a mat shaped sealmember provided in the present embodiment and a floor plate, inparticular, FIG. 7( a) is a perspective view of a state before the matshaped seal member is attached to the floor plate, and FIG. 7 (b) is aperspective view of a state in which the mat shaped seal member isattached to the floor plate.

FIG. 8 is a perspective view of a state where a mat shaped seal memberis removed from a state illustrated in FIG. 4.

FIG. 9 is a plan view of a part of a floor plate where a mat shaped sealmember provided in the present embodiment is removed.

FIG. 10 is an enlarged view of a cross section A of FIG. 9.

FIG. 11 is an enlarged view of a cross section B of FIG. 9.

FIG. 12 is a cross sectional view of a main part side where a mat shapedseal member according to the present embodiment is attached in a stateillustrated in FIG. 10.

DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment of a pilot valve attachment structure of aconstruction machine according to the present invention will bedescribed with reference to the drawings.

A construction machine provided with a pilot valve attachment structureaccording to the present invention, for example, constitutes a smallsized machine and is a compact excavator whose operation space of anoperation device to be arranged in an operator's cab is relativelynarrow. As illustrated in FIG. 1, the compact excavator includes atravel base 1, an upperstructure 2 that is arranged on the travel base1, and a working device 3 that is attached to the upperstructure 2 withbeing rotatable in a vertical direction. The working device 3 includes aboom 4 to be attached to the upperstructure 2, an arm 5 to be attachedto a tip of the boom 4, and a bucket 6 to be attached to a tip of thearm 5. The upperstructure 2 is provided with an operator's cab 7 and acounterweight 8 for securing weight balance. A machine room 9 in whichan engine, a hydraulic pump, etc., are accommodated is arranged betweenthe operator's cab 7 and the counterweight 8. In the operator's cab 7,an operator's seat 10 on which an operator sits is arranged, and asillustrated in FIG. 2, a travel operation device 11 including anoperation lever 16, an operation pedal 17, and a pilot valve 18 fortraveling is arranged in front of the operator's seat 10. Work operationdevices 10 a, 10 b are arranged respectively on both sides of theoperator's seat 10.

As illustrated in FIGS. 7 to 11, the pilot valve attachment structure ofa construction machine according to the present embodiment includes afloor plate 15 of the operator's cab 7 which is provided with a recessedpart 20. On a bottom part 20 a of the recessed part 20, a hole 20 b intowhich a casing 18 a forming an outer frame of the pilot valve 18 can beinserted is provided. As illustrated in FIGS. 10 and 11, the casing 18 aof the pilot valve 18 is attached to the bottom part 20 a of therecessed part 20 in a state where the casing 18 a of the pilot valve 18is inserted into the hole 20 b of the recessed part 20.

As illustrated in FIGS. 3 to 5 and 12, the present embodiment includes amat shaped seal member 21 for sealing a space that is formed around thecasing 18 a of the pilot valve 18 when the casing 18 a is inserted intothe hole 20 b of the recessed part 20. For example, the mat shaped sealmember 21 is made of a rubber member, and as illustrated in FIGS. 4 and6, consists of a first divided member 21 a and a second divided member21 b that are dividedly formed so as to interpose the casing 18 a of thepilot valve 18 therebetween.

As illustrated in FIGS. 6( b) and 7, the mat shaped seal member 21includes a projection part 22 on a lower side thereof. On the bottompart 20 a of the recessed part 20, a hole part 23 into which theprojection part 22 is inserted is provided. Furthermore, as illustratedin FIG. 5, the mat shaped seal member 21 is attached to the recessedpart 20 so that a top surface of the mat shaped seal member 21 formsapproximately the same plane as a top surface of the floor plate 15 andthe top surface of the mat shaped seal member 21 becomes in the heightequal to or higher than that of the floor plate 15.

As illustrated in FIG. 5, a mounting height of the pilot valve 18 to beattached to the recessed part 20 of the floor plate 15 is set such thata height position from the floor plate 15 to a top surface of the casing18 a of the pilot valve 18 is to be a relatively low height position Hthat is within a range where the floor plate 15 is not contact with theheel 30 a of a shoe 30 of an operator when the operator sitting on theoperator's seat 10 steps on the operation pedal 17. For example, theheight position H is set to be about 20 mm.

In the compact excavator provided with the pilot valve attachmentstructure according to the present embodiment, when an operator sittingon the operator's seat 10 operates the work operation devices 10 a, 10 bthat are illustrated in FIG. 2, the upperstructure 2 revolves or theworking device 3 rotates in a vertical direction to perform such asdigging work of earth and sand via the bucket 6. Furthermore, when anoperator sitting on the operator's seat 10 operates the operation lever16 of the travel operation device 11 or steps on the operation pedal 17,the pilot valve 18 activates and a travel directional control valve (notshown) is switched. Accordingly, pressure oil is supplied from ahydraulic pump accommodated in the machine room 9 to left and rightmotors via the travel directional control valve so that the travel base1 can travel.

In the pilot valve attachment structure according to the presentembodiment configured as above, because the casing 18 a of the pilotvalve 18 is attached to the bottom part 20 a of the recessed part 20 ofthe floor plate 15, the casing 18 a of the pilot valve 18 can beattached to the floor plate 15 such that the top surface of the pilotvalve 18 projecting from the top surface of the floor plate 15 is low.With this configuration, an oppressive sensation that an operatorsitting on the operator's seat 10 is likely to feel in a limited narrowoperation space can be reduced, and it is possible to secure acomfortable operability.

Because the recessed part 20 is formed in the floor plate 15, there isconcern that contaminants, such as mud attached to shoes of an operatoror muddy water generated at the time of washing the mud, may enter theinside of the pilot valve 18 through the recessed part 20, however, themat shaped seal member 21 that seals a space formed around the casing 18a of the pilot valve 18 can prevent the contaminants such as mud ormuddy water from entering the inside of the pilot valve 18.

Furthermore, in the present embodiment, because the mat shaped sealmember 21 is made of a rubber member, the mat shaped seal member 21 canbe bended due to elasticity and is easily attached to or removed fromthe recessed part 20 of the floor plate 15.

Still further, in the present embodiment, because the mat shaped sealmember 21 is dividedly formed into the first divided member 21 a and thesecond divided member 21 b so as to be separated with each other, anoperation for disposing the mat shaped seal member 21 around the casing18 a of the pilot valve 18 can be easily performed.

Still further, in the present embodiment, because the projection part 22of the mat shaped seal member 21 is inserted into the hole part 23 ofthe floor plate 15, it is possible to easily position the mat shapedseal member 21 within the recessed part 20 and to stably hold the matshaped seal member 21 which is attached to the recessed part 20 of thefloor plate 15, without causing any positional deviation with respect tothe recessed part 20.

Still further, in the present embodiment, because the mat shaped sealmember 21 is attached to the recessed part 20 such that the top surfaceof the mat shaped seal member 21 forms approximately the same plane asthat of the floor plate 15 and the top surface of the mat shaped sealmember 21 becomes in the height equal to or higher than that of thefloor plate 15, contaminants such as mud or muddy water hardly enter therecessed part 20, and thus it is possible to certainly prevent thecontaminants from entering the inside of the pilot valve 18.

EXPLANATION OF REFERENCES

1 travel base2 upperstructure3 working device10 operator's seat11 travel operation device15 floor plate18 pilot valve18 a casing20 recessed part20 a bottom part20 b hole21 mat shaped seal member21 a first divided member21 b second divided member21 c hole22 projection part23 hole part

1. A pilot valve attachment structure of a construction machine thatincludes a travel base, an upperstructure arranged on the travel base, aworking device attached to the upperstructure, an operator's seatarranged on a floor plate that is formed on the upperstructure, and atravel operation device arranged in front of the operator's seat andhaving a pilot valve, the pilot valve included in the travel operationdevice being attached to the floor plate, wherein a recessed part havinga hole, into which a casing forming an outer frame of the pilot valvecan be inserted, on a bottom part thereof is provided on the floorplate, the casing of the pilot valve is attached to the bottom part ofthe recessed part in a state where the casing of the pilot valve isinserted into the hole of the recessed part, and a mat shaped sealmember for sealing a space that is formed around the casing of the pilotvalve when the casing is inserted into the hole of the recessed part. 2.The pilot valve attachment structure of a construction machine accordingto claim 1, wherein the mat shaped seal member is made of a rubbermember.
 3. The pilot valve attachment structure of a constructionmachine according to claim 2, wherein the mat shaped seal memberconsists of a first divided member and a second divided member that aredividedly formed so as to interpose the casing of the pilot valvetherebetween.
 4. The pilot valve attachment structure of a constructionmachine according to claim 3, wherein the mat shaped seal memberincludes a projection part on a lower side thereof, and a hole part intowhich the projection part is inserted is formed on the bottom part ofthe recessed part.
 5. The pilot valve attachment structure of aconstruction machine according to claim 4, wherein the mat shaped sealmember is attached to the recessed part so that a top surface of the matshaped seal member forms approximately the same plane as a top surfaceof the floor plate and the top surface of mat shaped seal member becomesin the height equal to or higher than that of the floor plate.